Video broadcasting standards for digital television, such as the ATSC (Advanced Television Systems Committee) specification in the United States and the family of DVB (Digital Video Broadcasting) international standards, allow broadcasters to transmit digital content in a variety of resolutions and formats, such as 480p (e.g., 720×480 at 60 frames per second), 1080i (e.g., 1920×1080 at 60 fields per second), or 720p (1280×720 at 60 frames per second). Typically, a broadcasting station will allocate one or more channels for a particular broadcast, where each channel utilizes a single transmission format. For example, a sports station may broadcast a football game in 720p in one channel and in 480p in another channel. Broadcasting stations may prefer to use progressive transmission mode (e.g., 720p) for sports or movies, and interlaced transmission (e.g., 1080i) for regular programming (e.g., news and daytime TV series).
As more and more consumers invest into 1080p HDTVs, there is an increased interest from broadcasters to offer premium programming, such as movies and special sports broadcasts, using 1080p (e.g., 1920×1080 at 60 or 50 frames per second) transmission formats. Since many older receivers and TV sets may not be able to decode 1080p broadcasts, to accommodate backwards compatibility with those sets, broadcasters could transmit both a 720p or 1080i stream and a 1080p stream on two separate channels; however, such solutions require at least twice the bandwidth of a traditional 720p or 1080i high definition (HD) broadcast.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. Similarly, issues identified with respect to one or more approaches should not assume to have been recognized in any prior art on the basis of this section, unless otherwise indicated.